Physical measurements of solar ultraviolet radiation (UVB) and epidemiological data on skin cancer, including malignant melanoma, are collected and analyzed. These studies supply scientific evidence related o the potential consequences of continued ozone depletion and climate change (i.e., global warming), and thus may help develop policy relative to man-made atmospheric pollutants and international agreements to ban their use, such as the Montreal Protocol. Despite reports of recent stratospheric ozone depletion detected by satellites, our surface-based measurements of solar ultraviolet radiation of 290nm to 330nm wavelengths (UVB) continue to show no increasing trends at urban locations within the United States. The results also agree for rural areas, across continents, and in both hemispheres. For several U.S. locations, trends in incidence and mortality rates for malignant skin melanoma are compared with annual and monthly variations in solar UVB flux. Though UVB exposure is associated with increased risk, changes in stratospheric ozone depletion do not appear to be responsible for recent worldwide increases in the incidence of melanoma and skin cancer. Age and cohort analyses of skin melanoma mortality rates indicate that males born during the 1950s, and females born during the 1930s were at highest risk. Decreasing trends were noted among young cohorts and age groups under 30. Without additional increases in UVB exposure, age-adjusted skin melanoma mortality rates are projected to decline early in the 21st century.